Semiconductor device and manufacturing method of the same

ABSTRACT

A semiconductor device includes: a sensor element having a plate shape with a surface and including a sensor structure disposed in a surface portion of the sensor element; and a plate-shaped cap element bonded to the surface of the sensor element. The cap element has a wiring pattern portion facing the sensor element. The wiring pattern portion connects an outer periphery of the surface of the sensor element and the sensor structure so that the sensor structure is electrically coupled with an external element via the outer periphery. The sensor element does not have a complicated multi-layered structure, so that the sensor element is simplified. Further, the dimensions of the device are reduced.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on Japanese Patent Applications No.2007-174028 filed on Jul. 2, 2007, and No. 2008-4144 filed on Jan. 11,2008, the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a semiconductor device and amanufacturing method of a semiconductor device.

BACKGROUND OF THE INVENTION

Conventionally, a semiconductor dynamic quantity sensor has beenproposed which has a movable portion with a beam-like structure and afixed portion, and detects a dynamic quantity such as an acceleration, ayaw rate, vibration, or the like by detecting, e.g., a change in thecapacitance between the movable portion and the fixed portion (see,e.g., Patent Documents 1 to 3). In each of Documents 1 to 3, asemiconductor dynamic quantity sensor is shown in which a movableportion with a beam-like structure and a fixed portion, each functioningas a sensing portion, are formed on a multilayer SOI substrate, andwiring connecting the individual portions is made of polysilicon or thelike.

In Patent Document 4, a semiconductor dynamic quantity sensor isproposed which can prevent the entrance of water or a foreign substanceinto a movable portion by covering the movable portion with a capmember. In the semiconductor dynamic quantity sensor shown in PatentDocument 4, the cap member is provided with a large number of throughholes, and wire bonding is performed directly to wire bonding padsprovided on an SOI substrate formed with the movable portion and a fixedportion, so that the wires are used as a replacement for a wiring layer.

In Patent Document 5, a semiconductor dynamic quantity sensor isproposed which has a structure obtained by laminating, on a siliconlayer composing an SOI substrate and provided with a movable portion orthe like, a silicon layer composing another SOI substrate and providedwith a signal processing circuit via an annular bump. In Patent Document6, another example of the annular bump is proposed. In a sensor havingsuch a structure, a wiring layer is provided from a signal processingcircuit to electrically connect the signal processing circuit and theoutside, and the wiring layer is extracted crosswise to the outside ofthe annular bump, while it is insulated from the annular bump.

Patent Document 1: JP-H9-129898 A

Patent Document 2: JP-H11-295336 A

Patent Document 3: JP-H6-123628 A

Patent Document 4: JP-2004-333133 A

Patent Document 5: JP-2004-311951 A

Patent Document 6: JP-H11-94506 A

However, each of the technologies described in Patent Documents 1 to 3has the problem that, since the wiring layer made of a polysilicon layeris formed on the same substrate formed with the sensing portion, themanufacturing process is complicated, and the yield of the manufacturedsemiconductor dynamic quantity sensor lowers.

With the technology described in Patent Document 4, it is necessary toform the large number of holes extending through the cap member.Moreover, since the bonding wires are connected to the wire bonding padsusing a bonding tool, the large-sized through holes should be formed tokeep the tool from contact with the sidewall surfaces of the throughholes. This leads to the problem that a semiconductor chip formed withthe semiconductor dynamic quantity sensor has a large chip size.

With the technology described in Patent Document 5, since the wiringlayer crosses the annular bump, the bump and the wiring layer should beisolated with an insulator layer to be electrically insulated from eachother. This leads to the problem that the structure of the semiconductordynamic quantity sensor is complicated.

Thus, it is required to simplify the structure of a sensor in asemiconductor device, and to reduce a chip size.

SUMMARY OF THE INVENTION

In view of the above-described problem, it is an object of the presentdisclosure to provide a semiconductor device. It is another object ofthe present disclosure to provide a manufacturing method of asemiconductor device.

According to a first aspect of the present disclosure, a semiconductordevice includes: a sensor element having a plate shape with a surfaceand including a sensor structure disposed in a surface portion of thesensor element; and a plate-shaped cap element bonded to the surface ofthe sensor element. The cap element has a wiring pattern portion facingthe sensor element; and the wiring pattern portion connects an outerperiphery of the surface of the sensor element and the sensor structureso that the sensor structure is electrically coupled with an externalelement via the outer periphery.

In the above device, since the wiring pattern portion is disposed in thecap element, the sensor element does not have a complicatedmulti-layered structure. Thus, the structure of the sensor element issimplified. Further, the dimensions of the device are also reduced.

According to a second aspect of the present disclosure, a semiconductordevice includes: a first chip having a plate shape with a first surfaceand including a first IC circuit portion, which is disposed in a firstsurface portion of the first chip; and a second chip having a plateshape with a second surface and including a second IC circuit portion,which is disposed in a second surface portion of the second chip. Thefirst chip further includes a first wiring pattern portion comprising afirst insulating film, a first wiring layer, a second insulating filmand a second wiring layer. The first insulating film is disposed on thefirst IC circuit portion. The first wiring layer is patterned on thefirst insulating film and coupled with the first IC circuit portion. Thesecond insulating film is disposed on the first wiring layer. The secondinsulating film has a first opening so that the first wiring layer isexposed from the second insulating film via the first opening. Thesecond wiring layer is disposed on the first wiring layer exposed in thefirst opening. The second chip includes a second wiring pattern portioncomprising a third insulating film, a third wiring layer, a fourthinsulating film and a fourth wiring layer. The third insulating film isdisposed on the second IC circuit portion. The third wiring layer ispatterned on the third insulating film and coupled with the second ICcircuit portion. The fourth insulating film is disposed on the thirdwiring layer. The fourth insulating film has a second opening so thatthe third wiring layer is exposed from the fourth insulating film viathe second opening. The fourth wiring layer is disposed on the thirdwiring layer exposed from the second opening. The surface of the firstchip faces the surface of the second chip. The second wiring layer ofthe first wiring pattern portion of the first chip and the fourth wiringlayer of the second wiring pattern portion of the second chip are bondedto each other.

Each wiring pattern portion is disposed on a respective chip so that thewiring pattern portion is not disposed in a respective circuit portion.Accordingly, the structure of each circuit portion is simplified, andthe dimensions of the device are also reduced.

According to a third aspect of the present disclosure, a method formanufacturing a semiconductor device includes: preparing a sensorelement having a plate shape with a surface, and forming a sensorstructure in a surface portion of the sensor element; preparing aplate-shaped cap element having a wiring pattern portion, and patterningthe wiring pattern portion to bond with the sensor element in such amanner that an outer periphery of the surface of the sensor element isconnected to the sensor structure with the wiring pattern portion; andbonding the cap element and the sensor element to connect the wiringpattern portion to the sensor structure.

In the above method, since the sensor structure is only disposed in thesensor element, the sensor element does not have a complicated wiringstructure. Thus, a step for forming the sensor element is simplified.Further, since the wiring pattern portion is formed in the cap element,a step of forming the cap element is also simplified. Thus, the methodfor manufacturing the semiconductor device is simplified, and theyielding ratio of the device is improved.

According to a fourth aspect of the present disclosure, a method formanufacturing semiconductor devices includes: preparing a sensor waferhaving a plurality of sensor elements, each of which has a plate shapewith a surface, and forming a sensor structure in a surface portion ofeach sensor element; preparing a cap wafer having a plurality ofplate-shaped cap elements, each of which has a wiring pattern portion tobe bonded to a respective sensor element, and patterning each of thewiring pattern portions to connect an outer periphery of a respectivesensor element and a respective sensor structure; bonding the sensorwafer and the cap wafer to connect each wiring pattern portion to arespective sensor structure; and dividing the cap wafer and the sensorwafer into a plurality of sensor chips.

In the above method, the step for forming the sensor element issimplified, and the step of forming the cap element is also simplified.Thus, the method for manufacturing the semiconductor device issimplified, and the yielding ratio of the device is improved. Further,multiple sensor chips are formed at the same time.

According to a fifth aspect of the present disclosure, a method formanufacturing a semiconductor device includes: preparing a first chiphaving a plate shape with a surface, forming a first IC circuit portionin a surface portion of the first chip, and forming a first wiringpattern portion on the first IC circuit portion, the first wiringpattern portion comprising a first insulating film, a first wiringlayer, a second insulating film and a second wiring layer, wherein thefirst insulating film is formed on the first IC circuit portion, thefirst wiring layer is patterned on the first insulating film to beconnected to the first IC circuit portion, the second insulating film isformed on the first wiring layer and has a first opening to expose thefirst wiring layer via the first opening, and the second wiring layer isformed on the first wiring layer exposed from the second insulating filmvia the opening; preparing a second chip having a plate shape with asurface, forming a second IC circuit portion in a surface portion of thesecond chip, and forming a second wiring pattern portion on the secondIC circuit portion, the second wiring pattern portion comprising a thirdinsulating film, a third wiring layer, a fourth insulating film and afourth wiring layer, wherein the third insulating film is formed on thesecond IC circuit portion, the third wiring layer is patterned on thethird insulating film to be connected to the second IC circuit portion,the fourth insulating film is formed on the third wiring layer and has asecond opening to expose the third wiring layer via the second opening,and the fourth wiring layer is formed on the third wiring layer exposedfrom the fourth insulating film via the second opening; and facing thesurface of the first chip and the surface of the second chip, andbonding the second wiring layer of the first wiring pattern portion ofthe first chip and the fourth wiring layer of the second wiring patternportion of the second chip.

Each wiring pattern portion is disposed on a respective chip so that thewiring pattern portion is not disposed in a respective circuit portion.Accordingly, the structure of each circuit portion is simplified, andthe dimensions of the device are also reduced. Further, the first chipis easily connected to the second chip. Thus, the manufacturing methodof the device is simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a plan view of a semiconductor dynamic quantity sensoraccording to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view of the sensor shown in FIG. 1 along theline II-II;

FIG. 3A is a plan view of a sensor portion, and FIG. 3B is a plan viewof a cap portion;

FIGS. 4A to 4C are cross-sectional views illustrating the steps ofmanufacturing the sensor portion of the semiconductor dynamic quantitysensor according to the first embodiment;

FIGS. 5A to 5D are cross-sectional views illustrating the steps ofmanufacturing the cap portion of the semiconductor dynamic quantitysensor according to the first embodiment;

FIG. 6 is a view illustrating the manufacturing step of bonding thesensor portion and the cap portion of the semiconductor dynamic quantitysensor according to the first embodiment;

FIG. 7 is a view showing a plurality of semiconductor dynamic quantitysensors formed on a single silicon wafer;

FIG. 8 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a second embodiment of the presentinvention;

FIG. 9 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a third embodiment of the presentinvention;

FIG. 10 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a fourth embodiment of the presentinvention;

FIG. 11 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a fifth embodiment of the presentinvention;

FIG. 12 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a sixth embodiment of the presentinvention;

FIG. 13 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a seventh embodiment of the presentinvention;

FIG. 14 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to an eighth embodiment of the presentinvention;

FIG. 15 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a ninth embodiment of the presentinvention;

FIG. 16 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a tenth embodiment of the presentinvention;

FIGS. 17A to 17C are cross-sectional views illustrating the steps ofmanufacturing the sensor portion according to the tenth embodiment;

FIG. 18 is a plan view of the cap portion according to an eleventhembodiment of the present invention;

FIG. 19 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a twelfth embodiment of the presentinvention;

FIG. 20 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a thirteenth embodiment of the presentinvention;

FIG. 21 is a schematic cross-sectional view of a semiconductor deviceaccording to a fourteenth embodiment of the present invention;

FIG. 22 is a view showing the step of manufacturing the semiconductordevice shown in FIG. 21;

FIG. 23 is a schematic cross-sectional view of a semiconductor deviceaccording to a fifteenth embodiment of the present invention;

FIG. 24 is a plan view of a semiconductor dynamic quantity sensoraccording to a sixteenth embodiment of the present invention;

FIG. 25 is a cross-sectional view along the line XXV-XXV of FIG. 24;

FIG. 26 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to a seventeenth embodiment of the presentinvention;

FIG. 27 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to an eighteenth embodiment of the presentinvention;

FIG. 28A is a schematic plan view of a semiconductor dynamic quantitysensor according to a nineteenth embodiment of the present invention,and FIG. 28B is a cross-sectional view along the line XXVIIIB-XXVIIIB ofFIG. 28A; and

FIG. 29A is a schematic plan view of a semiconductor dynamic quantitysensor according to a twentieth embodiment of the present invention, andFIG. 29B is a cross-sectional view along the line XXIX-XXIX of FIG. 29A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Referring now to the drawings, the first embodiment of the presentinvention will be described hereinbelow. A semiconductor dynamicquantity sensor as a semiconductor device shown below is a dynamicquantity sensor, such as an acceleration sensor or an angular velocitysensor (Gyro sensor) having a movable portion, which is used to detect,e.g., the acceleration or angular velocity of a vehicle. In thesemiconductor device, an integrated circuit such as an IC or an LSI, asemiconductor dynamic quantity sensor (an acceleration sensor, anangular velocity sensor (Gyro sensor), or the like) having a movableportion, and a MEM oscillator are protected with a cap. The device issuitably used for an acceleration sensor or an angular velocity sensor(Gyro sensor).

FIG. 1 is a plan view of a semiconductor dynamic quantity sensoraccording to the first embodiment. FIG. 2 is a cross-sectional view ofthe sensor 1 shown in FIG. 1 along the line II-II. FIG. 3A is a planview of a sensor portion 10, and FIG. 3B is a plan view of a cap portion20, each showing a plane in which the sensor portion 10 and the capportion 20 oppose each other. In FIG. 3B, a first insulating film 22 anda second insulating film 24 are omitted. A description will be givenhereinbelow of a structure of the semiconductor dynamic quantity sensorwith reference to FIGS. 1 to 3.

As shown in FIG. 2, the semiconductor dynamic quantity sensor includesthe plate-like sensor portion 10, and the plate-like cap portion 20which are laminated on each other.

The sensor portion 10 is provided with a sensing portion for detecting aphysical quantity such as an acceleration. The sensor portion 10comprises an SOI substrate comprising a first silicon layer 11, a secondsilicon layer 12, and an insulating layer 13 interposed between thesilicon layers 11 and 12, and a wiring layer 14 provided on the firstsilicon layer 11. For each of the silicon layers 11 and 12, e.g., N-typemonocrystalline silicon is used. For the insulating layer 13, e.g., SiO₂is used. For the wiring layer 14, e.g., Al is used.

The sensing portion is provided in a surface layer portion of a surfaceof the plate-like first silicon layer 11 having the surface andcomposing the SOI substrate. Specifically, as shown in FIG. 1, the firstsilicon layer 11 is formed with movable electrode fixing portions 15, amovable electrode portion 16, fixed electrode portions 17, a connectionportion 18, and a peripheral portion 19.

The movable electrode fixing portions 15 are each in the shape of ablock and provided at two positions on the insulating layer 13. Themovable electrode portion 16 is disposed between these movable electrodefixing portions 15. As shown in FIG. 3A, the movable electrode portion16 includes a linear part 16 a connecting the movable electrode fixingportions 15, spring parts 16 b each perpendicular to the linear part 16a, and a bar-shaped electrode part 16 c. As a result of disposing themovable electrode 16 between the movable electrode fixing portions 15,the movable electrode 16 is in a state floating over the second siliconlayer 12.

The bar-shaped fixed electrode portions 17 are disposed at positionseach opposing the electrode part 16 c of the movable electrode portion16 on the insulating layer 13. Although the electrode part 16 c and thefixed electrode portions 17 shown in the embodiment are each minimum innumber, in an actual situation, a larger number of the electrode parts16 c and a larger number of the fixed electrode portions 17 are arrangedin a comb-teeth configuration to compose a comb-teeth electrode, i.e., acapacitor.

With such a structure, when the semiconductor dynamic quantity sensorreceives an acceleration (or an angular velocity) from the outside, thespring parts 16 b of the movable electrode portion 16 contract so thatthe electrode part 16 c of the movable electrode portion 16 movesrelative to the fixed electrode portion 17 at the fixed position in thedirection in which the linear part 16 a of the movable electrode portion16 extends. Therefore, by detecting the capacitance value of thecapacitor comprising the fixed electrode portions 17 and the electrodepart 16 c, the acceleration or the angular velocity received by thesemiconductor dynamic quantity sensor can be obtained. The movableelectrode fixing portions 15, the movable electrode portion 16, and thefixed electrode portions 17 each composing the comb-teeth structure willbe hereinafter referred to as sensor structures.

The connection portion 18 functions as a terminal for electricallyconnecting the semiconductor dynamic quantity sensor and the outside. Asshown in FIG. 2, since the wiring layer 14 is provided on the firstsilicon layer 11, the semiconductor dynamic quantity sensor and theoutside can be electrically connected via the wiring layer 14.

As shown in FIG. 3A, the peripheral portion 19 is provided to encirclethe foregoing sensor structures once, and also encircle the connectionportion 18 once. It will be easily appreciated that there is nooperational problem even when the connection portion 18 is notcompletely encircled once. That is, the region provided with the sensorstructures and the region provided with the connection portion 18connecting to the outside are isolated by the peripheral portion 19.

On the other hand, the cap portion 20 prevents the entrance of water ora foreign substance into the sensor structures described above, and iscomprised of a silicon substrate 21, a first insulating film 22, a firstwiring layer 23, a second insulating film 24, and a second wiring layer25. The first insulating film 22 and the second insulating film 24 maybe made of either the same material or different materials. The sameholds true for the first wiring layer 23 and the second wiring layer 25.The first wiring layer 23, the second insulating film 24, and the secondwiring layer 25 correspond to wiring pattern portions.

The silicon substrate 21 has a recessed part 21 a in which a sidesurface of a quadrilateral is recessed toward the other side surfacethereof. The recessed part 21 a exposes the connection portion 18 fromthe silicon substrate 21 when the cap portion 20 and the sensor portion10 are superimposed on each other.

The first insulating film 22 is formed on the surface of the siliconsubstrate 21 opposing the sensor portion 10. The first insulating film22 insulates the first wiring layer 23 and the silicon substrate 21 fromeach other. The first wiring layer 23 is patterned and provided on thefirst insulating film 22.

The second insulating film 24 is formed on the first wiring layer 23 soas to cover the first wiring layer 23. Of the second insulating film 24,the respective portions opposing the fixed electrode portions 17, themovable electrode fixing portions 15, and the connection portion 18 areopened.

The second wiring layer 25 is patterned and provided on the secondinsulating film 24 thus provided with the openings. That is, the secondwiring layer 25 includes a wiring part 25 a bonded to the fixedelectrode portions 17, the movable electrode fixing portions 15, and theconnection portion 18 of the sensor portion 10, and a hermeticallysealing part 25 b bonded to the peripheral portion 19 of the sensorportion 10. The hermetically sealing part 25 b is provided to traversethe first wiring layer 23. In other words, the hermetically sealing part25 b is disposed to span over the first wiring layer 23.

In the second wiring layer 25 with such a wiring structure, therespective heights of the wiring part 25 a and the hermetically sealingpart 25 b from the surface of the silicon substrate 21 are the same.

In the present embodiment, the recessed part 21 a is provided in oneside surface of the silicon substrate 21, so that the second wiringlayer 25 corresponding to the peripheral portion 19 opposing therecessed part 21 a is not provided. Accordingly, the second wiring layer25 is provided to encircle the sensor structures of the sensor portion10 at least once.

As described above, in the opened portions of the second insulating film24, the first wiring layer 23 and the wiring part 25 a of the secondwiring layer 25 are electrically connected. On the other hand, in theunopened portion of the second insulating film 24; i.e., in the area ofthe second insulating film 24 opposing the peripheral portion 19, thehermetically sealing part 25 b of the second wiring layer 25 is formedon the second insulating film 24, so that the first wiring layer 23 andthe hermetically sealing part 25 b are insulated. That is, it ispossible to provide a wiring configuration in which the first wiringlayer 23 and the hermetically sealing part 25 b cross each other, andelectrically connect the connection portion 18 and each of the fixedelectrode portions 17 and the movable electrode fixing portions 15 ofthe sensor unit 10 across the peripheral portion 19.

For the first insulating film 22 and the second insulating film 24 eachmentioned above, SiO₂ or Si₃N₄, e.g., is used. For the first wiringlayer 23 and the second wiring layer 25, Al or polysilicon, e.g., isused.

Then, the second wiring layer 25 of the cap portion 20 is solidly bondedto the peripheral portion 19 of the sensor portion 10 by a method suchas, e.g., direct bonding. As a result, a configuration as shown in FIG.2 is provided in which the sensor structures are hermetically sealed bythe second silicon layer 12, the insulating layer 13, and the peripheralportion 19 of the sensor unit 10 and by the second wiring layer 25, thehermetically sealing part 25 b of the second wiring layer 25, the secondinsulating film 24, and the first insulating film 22 of the cap portion20.

That is, by sealing the sensor structures, it is possible to prevent theentrance of water or a foreign substance into the sealed space. Thereare cases where the space is evacuated and where the space contains aninert gas such as N₂ or He, or an atmosphere. In the present embodiment,the space is in vacuum.

Additionally, as shown in FIG. 1, the recessed part 21 a provided in thesilicon substrate 21 of the cap portion 20 exposes the connectionportion 18 of the sensor portion 10 from the silicon substrate 21. Tothe connection portion 18 exposed from the silicon substrate 21, bondingwires 31 are bonded, as shown in FIG. 2, to electrically connect thesemiconductor dynamic quantity sensor to the outside. The foregoing isthe description of the overall structure of the semiconductor dynamicquantity sensor according to the present embodiment.

Next, a description will be given of a method for manufacturing thesemiconductor dynamic quantity sensor described above. It is assumedhereinbelow that a plurality of the sensor portions 10 are formed on asingle silicon wafer. FIGS. 4A to 4C are cross-sectional viewsillustrating the steps of manufacturing the sensor portions 10 of thesemiconductor dynamic quantity sensor according to the presentembodiment.

First, in the step shown in FIG. 4A, an SOI substrate is prepared.Specifically, using a monocrystalline silicon wafer as the secondsilicon layer 12 as a supporting base, a SiO₂ film with a thicknessranging from 0.1 to 2 μm is formed as the insulating layer 13 on thesupporting base. Further, a silicon layer as the first silicon layer 11is bonded onto the SiO₂ film by a wafer bonding method, whereby the SOIsubstrate is prepared.

In the present embodiment, an N-type (100) silicon layer having aspecific resistance ranging from, e.g., 0.001 Ω·cm to 0.02 Ω·cm is usedas the first silicon layer 11. As the second silicon layer 12, an N-type(100) silicon substrate having a specific resistance ranging from, e.g.,0.001 Ω·cm to 10 Ω·cm is used

The monocrystalline silicon substrate and the silicon layer, eachmentioned above, may also have a P-type conductivity. As the crystallineorientation, not only the (100) type, but also another typically usedorientation may be used. It will be easily understood that the SOIsubstrate may also be formed by depositing, as silicon, not onlymonocrystalline silicon, but also polycrystalline silicon containing animpurity at a high concentration by a CVD method or the like. Besides asilicon substrate, there can be used a glass substrate, metal, ceramics,another semiconductor material, or the like. The thickness of each ofthe first and second silicon layers 11 and 12 can be set arbitrarily toa value in the range of 1 μm to 500 μm.

In the step shown in FIG. 4B, an Al layer with a thickness ranging from0.1 μm to 2 μm is formed as the wiring layer 14 on the first siliconlayer 11 of the SOI substrate by, e.g., a CVD method. In this case, thewiring layer 14 is formed on the entire surface of the first siliconlayer 11.

Subsequently, in the step shown in FIG. 4C, trenches are formed in eachof the wiring layer 14 and the first silicon layer 11 by aphotolithographic/etching step to form the fixed electrode portions 17,the movable electrode fixing portions 15, the peripheral portion 19, andthe connection portion 18. In this case, the movable electrode portion16 is formed by removing the insulating layer 13 between the portion ofthe first silicon layer 11 serving as the movable electrode portion 16and the second silicon layer 12 with a vapor-phase or liquid-phase HF(hydrogen fluoride) etchant. By the foregoing steps, the sensor portion10 of the semiconductor dynamic quantity sensor is completed.

Next, a description will be given of a method for manufacturing the capportion 20. It is assumed hereinbelow that a plurality of the capportions 20 are formed on a single silicon wafer. FIGS. 5A to 5D arecross-sectional views illustrating the steps of manufacturing the capportions 20 of the semiconductor dynamic quantity sensor according tothe present embodiment.

First, in the step shown in FIG. 5A, the monocrystalline siliconsubstrate 21 having a specific resistance of, e.g., 0.01 Ω·cm orientedin the (100) plane is prepared, which is a so-called silicon wafer. Onthe silicon substrate 21, a Si₃N₄ film with a thickness ranging from 1μm to 2 μm is formed as the first insulating film 22. The Si₃N₄ film canbe formed by an LPCVD method or a plasma CVD method.

In the step shown in FIG. 5B, an Al layer with a thickness ranging from0.1 μm to 2 μm is formed on the first insulating film 22, and patternedby a photolithographic/etching step to form the first wiring layer 23.It is also possible to use a so-called mask vapor deposition methodusing a porous mask made of a metal such as stainless steel.

In the step shown in FIG. 5C, a SiO₂ film with a thickness ranging from0.5 μm to 4 μm is formed as the second insulating film 24 on the firstwiring layer 23 and the first insulating film 22. The second insulatingfilm 24 is formed to have a thickness sufficiently larger than that ofthe first wiring layer 23, and the surface of the second insulating film24 is planarized by a CMP method across the entire wafer. Instead ofplanarizing the second insulating film 24, it is also possible to formthe second wiring layer 25 sufficiently thick on the entire surface tobe formed in the next step, planarize the entire surface of the secondwiring layer 25 by a CMP method, and pattern the second wiring layer 25by a photolithographic/etching step. By patterning the SiO₂ film,opening parts 24 a exposing the first wiring layer 23 are formed in therespective portions of the SiO₂ film facing the fixed electrode portions17, the movable electrode fixing portions 15, and the connection portion18 of the sensor portion 10. The opening parts 24 a need not necessarilybe formed at positions exactly opposing the fixed electrode portions 17,the movable electrode fixing portions 15, and the connection portion 18of the sensor portion 10, and may also be formed at positions displacedfrom the exactly opposing positions. The opening parts 24 a providecontact between the first wiring layer 23 and the second wiring layer 25to be formed in the next step. At this time, the portion of the secondinsulating film 24 corresponding to at least the electrode part 16 c ofthe movable electrode portion 16 has been partially removed in the samemanner. This is for making the electrode part 16 c of the movableelectrode portion 16 less likely to come in contact with the cap portion20.

In the step shown in FIG. 5D, the wiring part 25 a and the hermeticallysealing part 25 b, each as the second wiring layer 25, are formed by amethod which forms and patterns an Al layer or a method using a mask. Asa result, the wiring part 25 a of the second wiring layer 25 and thefirst wiring layer 23 are connected to electrically conduct in theportions of the second insulating film 24 where the opening parts 24 aare provided.

In this case, the wiring part 25 a and the hermetically sealing part 25b are formed such that the wiring part 25 a and the hermetically sealingpart 25 b have equal heights from the surface of the silicon substrate21. The hermetically sealing part 25 b may be either electricallyfloating, or at a predetermined potential such as, e.g., a groundpotential as necessary. By the foregoing steps, the cap portion 20 ofthe semiconductor dynamic quantity sensor is completed. As the substrateof the cap portion 20, there can also be used a glass substrate, metal,ceramics, or another semiconductor material besides the siliconsubstrate 21.

Next, as shown in FIG. 6, the sensor portion 10 and the cap portion 20are bonded to each other. Specifically, the wiring layer 14 of thesensor portion 10 and the second wiring layer 25 of the cap portion 20are brought into opposing relation, the respective surfaces thereof areactivated by sputtering with argon ions or the like in high vacuum, andthen the wiring layers 14 and 25 are solidly bonded at a temperatureranging from a room temperature to 500° C. by a so-called direct bondingmethod, as shown in JP-H10-92702 A. In this manner, the peripheralportion 19 of the sensor portion 10 and the hermetically sealing part 25b of the cap portion 10 are bonded to hermetically seal the sensorstructures. On the other hand, by bonding the fixed electrode portions17, the movable electrode fixing portions 15, and the connection portion18 of the sensor portion 10 to the wiring part 25 a of the cap portion25, the sensor structures and the connection portion 18 of the sensorportion 10 are electrically connected.

In the present embodiment, the sensor portion 10 and the cap portion 20are bonded by direct bonding as described above. However, it is alsopossible to perform solder connection or the like by, e.g., forming ametal layer of Ni, Cu, Au, or the like on the wiring layer 14 of thesensor portion 10 and on the second wiring layer 25 of the cap portion20. Alternatively, it is also possible to provide connection using aconductive adhesive such as a silver paste, instead of performing solderconnection. According to the method, in the case of the direct bondingdescribed above, it is necessary for the wiring part 25 a and thehermetically sealing part 25 b to have equal heights from the surface ofthe silicon substrate 21 in the second wiring layer 25 of the capportion 20. However, in the case of using the solder connection or theconductive adhesive, a solder or the adhesive functions to adjust therespective heights of the wiring part 25 a and the hermetically sealingpart 25 b, so that the wiring part 25 a and the hermetically sealingpart 25 b need not have equal heights from the surface of the siliconsubstrate 21. That is, in the case of using the solder connection andthe conductive adhesive, the sensor structures can be hermeticallysealed by pressing the cap portion 10 against the sensor portion 10.

As described above, the sensor portion 10 and the cap portion 20 areformed on the respective silicon wafers, which are then laminated oneach other. As a result, as shown in FIG. 7, a plurality of thesemiconductor dynamic quantity sensors are formed on a wafer 40.Therefore, by cutting the wafer 40 shown in FIG. 7 by dicing, the wafer40 can be divided on a per chip basis to provide the individualsemiconductor dynamic quantity sensors.

It is to be noted that, in an actual situation, the sensor portions 10and the cap portions 20 are formed on the wafer 40 such that severalhundreds of semiconductor dynamic quantity sensors are included therein,and the wafer 40 is eventually divided on a per chip basis. On the otherhand, it is also possible to manufacture the semiconductor dynamicquantity sensors by discretely forming the sensor portions 10 and thecap portions 20, and bonding the individual sensor portions 10 and theindividual cap portions 20, as shown in FIG. 6.

Thereafter, each of the semiconductor dynamic quantity sensors ismounted on a circuit board or the like not shown, and the connectionportion 18 and an electric circuit, not shown, are wire bonded to allowan electric signal in accordance with a physical quantity produced inthe sensor structures to be outputted to the outside of thesemiconductor dynamic quantity sensor.

As described above, the present embodiment is characterized in that amultilayer structure comprising the first insulating film 22, the firstwiring layer 23, the second insulating film 24, and the second wiringlayer 25 is provided on the surface of the cap portion 20 of thesemiconductor dynamic quantity sensor which opposes the sensor portion10. This obviates the necessity to provide a complicated wiring layer inthe sensor portion 10 provided with the sensor structures serving as thesensing portion, allows the simplification of the structure of thesensor portion 10, and thereby allows the simplification of thestructure of the semiconductor dynamic quantity sensor.

By providing the cap portion 20 with the wiring layer and causing it tofunction as a hermetical seal, the step of providing the sensor portion10 with the wiring layer becomes unnecessary, and it is no morenecessary to provide the sensor portion 10 with a multilayer structure.As a result, it is possible to simplify the process of manufacturing thesensor portion 10, and also simplify the process of manufacturing theentire semiconductor dynamic quantity sensor. This allows an improvementin the yield of the semiconductor dynamic quantity sensor and a costreduction.

Additionally, the wiring part 25 a and the hermetically sealing part 25b, each composing the second wiring layer 25, have equal heights fromthe surface of the silicon substrate 21. This allows the connectionportion 18 and the sensor structures to be electrically connected by thewiring part 25 a by merely bonding the sensor portion 10 and the capportion 20, and also allows the sensor structures to be hermeticallysealed by the hermetically sealing part 25 b.

Moreover, the recessed part 21 a is provided in the cap portion 20 toexpose the connection portion 18 of the sensor portion 10 therefrom. Thearrangement can keep a tool for performing wire bonding from contactwith the cap portion 20, and also allows easy wire bonding to theconnection portion 18. As a result, it is also unnecessary to providethe cap portion 20 with through holes for wire bonding. This can preventan increase in the size of the cap portion 20, and therefore allows areduction in chip size.

Second Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the firstembodiment. In the first embodiment described above, the sensor portion10 of the semiconductor dynamic quantity sensor is provided with theconnection portion 18 for allowing electrical connection to the outside.The present embodiment has a characteristic structure which allowselectrical connection from the cap portion 20 to the outside.

FIG. 8 is a schematic cross-sectional view of a semiconductor dynamicquantity sensor according to the present embodiment. As shown in thedrawing, a structure is provided in which the connection portion 18 ofthe sensor portion 10 shown in FIG. 2 is not provided, and the sensorportion 10 has only the portion surrounded by the peripheral portion 19.On the other hand, the cap portion 20 has the same structure as in thefirst embodiment.

Therefore, as shown in FIG. 8, the size of the sensor portion 10 whichis not provided with the connection portion 18 is accordingly smallerthan the size of the sensor portion 10 shown in FIG. 2. When the sensorstructures of the sensor portion 10 are sealed by the hermeticallysealing part 25 b of the cap portion 20, the wiring part 25 a of the capportion 20, which are bonded to the connection portion 18 of the sensorportion 10 shown in FIG. 2, are exposed.

In the present embodiment, the exposed, i.e., unsealed wiring part 25 ais used as a pad in the sensor portion 10. As shown in FIG. 8, thebonding wires 31 are connected to the exposed wiring part 25 a toelectrically connect the semiconductor dynamic quantity sensor and theoutside.

In this manner, the wiring part 25 a of the cap portion 20 can beconnected to the outside. In this case, the size of the sensor portion10 is smaller than in the first embodiment, while the size of the capportion 20 remains unchanged. This allows the semiconductor dynamicquantity sensor shown in FIG. 2 to be reduced in size. Additionally, inthe present embodiment, the recessed part 21 a, which is provided in thesilicon substrate 21 of the cap portion 20 in the first embodiment, isprovided in the sensor portion 10. In the case of individual assembly,not wafer-to-wafer assembly, the recessed part 21 a may also beeliminated.

Third Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the secondembodiment. FIG. 9 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. The present embodiment has a configuration in which thewiring layer 14 is not provided on the first silicon layer 11 in thesensor portion 10 shown in FIG. 8, and the wiring part 25 a and thehermetically sealing part 25 b of the second wiring layer 25 of the capportion 20 are connected directly to the first silicon layer 11 of thesensor portion 10. Particularly in the case where P-type silicon is usedin the first silicon layer 11 and an Al layer is used as the secondwiring layer 25, the specific resistance of silicon is in the range of0.01 to 1 Ω·cm so that an ohmic contact is more easily made than withN-type silicon. Accordingly, P-type silicon at a relatively lowconcentration can be used.

When the cap portion 20 is bonded to the sensor portion 10 with such astructure, the Al layer can be bonded directly to the silicon layer at aroom temperature. In this case, it is possible to obviate the necessityfor the step of a thermal treatment or the like, and simplify themanufacturing process.

In addition, since the sensor portion 10 need not be provided with thewiring layer 14, it is possible to omit the step of manufacturing thewiring layer 14, and also simplify the structure of the sensor portion10.

Fourth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the firstembodiment. The present embodiment is characterized in that an ICcircuit portion is provided in the semiconductor dynamic quantitysensor, especially in the cap portion 20.

FIG. 10 is a schematic cross-sectional view of the semiconductor dynamicquantity sensor according to the present embodiment. As shown in thedrawing, an IC circuit portion 50 is provided on the surface of thesilicon substrate 21 composing the cap portion 20 which is opposite tothe surface provided with the first insulating film 22.

The IC circuit portion 50 is provided with circuits such as, e.g., anamplification circuit for amplifying a signal equivalent to a physicalquantity detected by the sensor portion 10 and an arithmetic operationcircuit for performing an arithmetic operation based on the signal. TheIC circuit portion 50 is formed during the manufacturing of the capportion 20, especially before multilayer wiring including the firstwiring layer 23 is formed.

To the IC circuit portion 50, a wire 32 is connected. The wire 32 isconnected to, e.g., the connection portion 18 of the sensor portion 10,to a circuit provided outside the semiconductor dynamic quantity sensor,or the like. Thus, the structure can be implemented in which the ICcircuit portion 50 is provided in the cap portion 20.

Fifth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the fourthembodiment. FIG. 11 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. As shown in the drawing, the IC circuit portion 50 isprovided on the surface of the silicon substrate 21 of the cap portion20 opposing the sensor portion 10.

Then, the first insulating film 22 is formed to cover the surface of thesilicon substrate 21 including the IC circuit portion 50, and the firstwiring layer 23, the second insulating film 24, and the second wiringlayer 25 are formed thereon in this order. In this case, an opening notshown is provided in the first insulating film 22, and a so-called ICchip manufacturing method can be used. Further, the wiring layer of theIC chip is made of Al or Cu so that a multilayer wiring layer can alsobe used. Electrical connection is provided between the IC circuitportion 50 and the first wiring layer 23 via the opening.

Such a structure of the cap portion 20 allows the step of providing thefirst insulating film 22 to be performed immediately after the ICcircuit portion 50 is provided on the surface of the silicon substrate21. Moreover, the wire 32 need not be connected to the IC circuitportion 50. In this manner, the step of manufacturing the cap portion 20according to the fourth embodiment can be simplified.

Sixth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the thirdembodiment. FIG. 12 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. As shown in the drawing, the cap portion 20 is bonded to thesensor portion 10 which is not provided with the connection portion 18.The IC circuit portion 50 is provided on the surface of the siliconsubstrate 21 of the cap portion 20 opposing the sensor portion 10.

In this manner, the structure can be implemented in which the IC circuitportion 50 is provided in the structure of FIG. 9. The same shall applyto the structure shown in FIG. 8. In this case, as shown in FIG. 10, theIC circuit portion 50 is provided in the structure shown in FIG. 8.

Seventh Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the firstembodiment. FIG. 13 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. As shown in the drawing, a plurality of the connectionportions 18 are provided in the sensor portion 10.

In the present embodiment, the bidirectional connection portion 18 isprovided in addition to the unidirectional connection portion 18 shownin FIG. 2. This allows the wires 31 to be connected in multipledirections from the sensor portion 10. In this case, in the cap portion20, the first wiring layer 23 is formed in the direction in which theconnection portions 18 are provided in the sensor portion 10 so as tospan over the peripheral portion 19 of the sensor portion 10. In thepresent embodiment also, the wiring part 25 a and the hermeticallysealing part 25 b of the second wiring layer 25 have equal heights fromthe surface of the silicon substrate 21.

Thus, the connection portions 18 can be provided in multiple directionsin the sensor portion 10. It is further possible to apply the presentembodiment to the second embodiment shown in FIG. 8, and provide theconnection portions 18 in multiple directions. It is also possible toform the peripheral portion 19 encircling the entire sensor portion 10once, and shield the inside of the peripheral portion 19 by connecting awire, not shown, to the peripheral portion 19.

In the present embodiment also, the structure can be implemented inwhich the IC circuit portion 50 is provided in the cap portion 20, inthe same manner as in, e.g., the fourth and fifth embodiments.

Eighth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the seventhembodiment. FIG. 14 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. As shown in the drawing, the recessed parts 21 a areprovided in the surface of the silicon substrate 21 of the cap portion20 opposing the sensor portion 10.

The recessed parts 21 a are provided in the region surrounded by thehermetically sealing part 25 b. Specifically, in the surrounded region,the recessed parts 21 a are formed in the area of the silicon substrate21 other than the portion where the wiring part 25 a and the sensorportion 10 are bonded, i.e., in the silicon substrate 21 opposing thesecond silicon layer 12 of the sensor portion 10. The recessed part 21 ais also provided in the area of the silicon substrate 21 opposing themovable electrode portion 16.

The recessed parts 21 a reduce the influence of electrical or mechanicalcontact or the like received by the sensor structures provided in thesensor portion 10 from the cap portion 20. Therefore, in the structureshown in FIG. 14, the three recessed parts 21 a are provided in thesilicon substrate 21. However, it is sufficient for the recessed part 21a to be provided at least in the area opposing the movable electrodeportion 16 which detects a physical quantity. Thus, it is possible toprovide the recessed parts 21 a in the silicon substrate 21 of the capportion 20, and reduce influence from the silicon substrate 21 to thesensor structures.

It is also possible to, e.g., provide the foregoing structure shown inFIG. 14 with the IC circuit portion 50 shown in FIG. 10. Alternatively,it is also possible to implement a structure as shown in FIGS. 8 and 9by eliminating the connection portion 18 of the sensor portion 10.

Ninth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the firstembodiment. The present embodiment is characterized in that the siliconsubstrate 21 of the cap portion 20 and the peripheral portion 19 of thesensor portion 10 are set at the same electric potential.

FIG. 15 is a schematic cross-sectional view of the semiconductor dynamicquantity sensor according to the present embodiment. As shown in thedrawing, an opening part 22 a and the opening part 24 a are provided inthe respective portions of the first insulating film 22 and the secondinsulating film 24, each composing the cap portion 20, which oppose theperipheral portion 19 provided at the outer edge portion of the firstsilicon layer 11. In the opening parts 22 a and 24 a, conduction contactportions 26 and 27 are formed, respectively.

The conduction contact portion 26 formed in the opening part 22 a of thefirst insulating film 22 corresponds to a first conduction contactportion. The conduction contact portion 27 formed in the opening part 24a of the second insulating film 24 corresponds to a second conductioncontact portion.

The conduction contact portion 26 functions to electrically connect thesilicon substrate 21 and the first wiring layer 23. The conductioncontact portion 27 functions to electrically connect the first wiringlayer 23 and the wiring part 25 a of the second wiring layer 25. By sucha structure, the silicon substrate 21, the conduction contact portion26, the first wiring layer 23, the conduction contact portion 27, thewiring part 25 a, the wiring layer 14, and the peripheral portion 19 ofthe first silicon layer 11 are brought into an electrically conductingstate, and set at the same potential.

In the structure, these conduction contact portions 26 and 27 areprovided along the entire peripheral portion 19 positioned at the outeredge portion of the first silicon layer 11. However, the conductioncontact portions 26 and 27 may also be provided along a part of theperipheral portion 19.

On the other hand, the potential of the second silicon layer 12 of thesensor portion 10 can be set by, e.g., connecting the second siliconlayer 12 onto a lead frame with silver paste or the like.

By thus providing the wiring layer of the cap portion 20 with theconduction contact portions 26 and 27 electrically connecting theperipheral portion 19 and the silicon substrate 21, the structure can beimplemented in which the semiconductor physical quantity sensor isprovided with a shield structure.

It is to be noted that what has been achieved in the second to eighthembodiments can also be achieved in the semiconductor dynamic quantitysensor shown in FIG. 15.

Tenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the ninthembodiment. The present embodiment is characterized in that theperipheral portion 19 of the first silicon layer 11 and the secondsilicon layer 12 are electrically connected in the sensor portion 10.

FIG. 16 is a schematic cross-sectional view of the semiconductor dynamicquantity sensor according to the present embodiment. The semiconductorphysical quantity sensor shown in FIG. 16 has a structure implemented byproviding the insulating layer 13 between the peripheral portion 19 andthe second silicon layer 12 of the structure shown in FIG. 15 withsubstrate contact parts 11 a for electrically connecting the peripheralportion 19 and the second silicon layer 12. The substrate contact parts11 a are formed of, e.g., polycrystalline (poly-) silicon.

The substrate contact parts 11 a may be formed either along the entireperipheral portion 19 provided in the first silicon layer 11, or along apart of the peripheral portion 19.

Next, a description will be given of a method for manufacturing thesensor portion 10 according to the present embodiment. FIGS. 17A to 17Care cross-sectional views illustrating the steps of manufacturing thesensor portion 10 according to the present embodiment.

First, in the step shown in FIG. 17A, a supporting base as the secondsilicon layer 12 is prepared, and a SiO₂ film with a thickness of 0.1 μmto 2 μm is formed as the insulating layer 13 on the supporting base.Then, by a photolithographic/etching step, opening parts 13 a exposingthe second silicon layer 12 are provided in the area of the insulatinglayer 13 where the peripheral portion 19 is provided.

Subsequently, in the step shown in FIG. 17B, a polysilicon layer as thefirst silicon layer 11 with a thickness of 3 μm to 100 μm is depositedon the insulating layer 13 by, e.g., a CVD method. In forming thepolysilicon layer by the CVD method, doped polysilicon at a highconcentration and with a low resistance can be obtained bysimultaneously supplying P, As, B, and the like as impurities. In thismanner, the substrate contact parts 11 a are formed in the opening parts13 a provided in the insulating layer 13, and the first silicon layer 11is formed. Then, the wiring layer 14 is formed on the first siliconlayer 11 in the same manner as in the step shown in FIG. 4B.

Thereafter, in the step shown in FIG. 17C, the peripheral portion 19 andthe sensor structures are formed in the first silicon layer 11 byperforming the same step as the step shown in FIG. 4C. In this manner,the structure can be obtained which has the substrate contact parts 11 aprovided between the peripheral portion 19 and the second silicon layer12, and electrically connects the peripheral portion 19 and the secondsilicon layer 12, whereby the sensor portion 10 according to the presentembodiment is completed.

By thus providing the substrate contact parts 11 a electricallyconnecting the peripheral portion 19 and the second silicon layer 12 tobe located therebetween, the second silicon layer 12 can be set at thesame potential as that of the silicon substrate 21 of the cap portion20, and a shield structure can be formed. Since this allows the secondsilicon layer 12 to reduce influence from the outside, a shield effecthigher than that of the structure shown in FIG. 15 can be obtained. Inthe case of forming the polysilicon layer by a CVD method in themanufacturing method, when the polysilicon layer is formed at a highertemperature ranging from, e.g., 900° C. to 1200° C., the portions of thesubstrate contact parts 11 a can be formed of monocrystalline silicon byepitaxial growth.

Eleventh Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor devices according to the ninth andtenth embodiments. In the structures according to the ninth and tenthembodiments described above, the conduction contact portions 26 and 27are provided along the entire peripheral portion 19 located at the outeredge portion of the first silicon layer 11, or along a part of theperipheral portion 19. However, it is also possible to adopt a structurein which a conduction contact portion is provided at one place.

FIG. 18 is a plan view of the cap portion 20 according to the presentembodiment. As shown in the drawing, a conduction contact portion 28 isprovided only at one place in the hermetically sealing part 25 b. Suchconduction contact portions 28 may also be provided at a plurality ofpositions. Thus, the conduction contact portion 28 can be providedsingly at one position.

Twelfth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the sixthembodiment. The present embodiment is characterized in that the sensorportion 10 bonded to the cap portion 20 is provided with bumps.

FIG. 19 is a schematic cross-sectional view of the semiconductor dynamicquantity sensor according to the present embodiment. As shown in thedrawing, bumps 60 for flip-chip mounting (ball bonding) are provided onthe connection portion 18 in the sensor portion 10. More specifically,the bumps 60 are provided on the wiring layer 14 of Al of the connectionportion 18. The plurality of bumps 60 are formed in the sensor portion10.

The cap portion 20 is formed to have a thickness ranging from, e.g., 10μm to 100 μm. On the other hand, the bumps 60 are formed to be higherthan the cap portion 20 relative to the sensor portion 10. As the bumps60, Au balls are formed by way of example. The bumps 60 may also beformed of Cu.

On the bumps 60, a circuit board 70 is flip-chip mounted. Since thebumps 60 are higher than the cap portion 20 relative to the sensorportion 10, the flat circuit board 70 can be bonded. When the heights ofthe bumps 60 are set to, e.g., about 30 μm, small-scale flip chipmounting (ball bonding) can be implemented.

Although the IC circuit portion 50 is formed in the cap portion 20, thecap portion 20 need not be provided with the IC circuit portion 50.

The bumps 60 are formed as follows. The SOI substrate is prepared, andthe wiring layer 14 is formed on the first silicon layer 11. Then, aresist is formed on the wiring layer 14, and patterned to expose theareas of the wiring layer 14 where the bumps 60 are to be formed.Thereafter, Cu plating, e.g., is performed with respect to the uppersurface of the resist, and then the resist is removed. As a result, thebumps 60 are left on the areas of the wiring layer 14 where the resistis opened. In this manner, the bumps 60 can be formed.

Then, after the bumps 60 are formed, the cap portion 20 is bonded to thesensor portion 10, as described above. Thereafter, the circuit board 70is prepared, and flip-chip mounted on the sensor portion 10 via thebumps 60, whereby the sensor shown in FIG. 19 is completed.

By thus providing the sensor portion 10 with the bumps, the circuitboard 70 can be flip-chip mounted on the sensor portion 10, and amultilayer structure can further be realized.

Thirteenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the twelfthembodiment. In the twelfth embodiment described above, the bumps 60 areformed to be higher than the cap portion 20 relative to the sensorportion 10. In the present embodiment, by contrast, the bumps 60 areformed to be lower than the cap portion 20.

FIG. 20 is a schematic cross-sectional view of the semiconductor dynamicquantity sensor according to the present embodiment. As shown in thedrawing, the bumps 60 are formed to be lower than the cap portion 20relative to the sensor portion 10. On the other hand, a depressedportion 71 is formed in the surface of the circuit board 70 opposing thecap portion 20. As a result, even when the circuit board 70 is flip-chipmounted on the sensor portion 10, the cap portion 20 is contained in thedepressed portion 71 in the circuit board 71. Therefore, the circuitboard 70 is mounted on the sensor portion 10 without contacting the capportion 20.

The depressed portion 71 in the circuit board 70 may also extend throughthe circuit board 70. In this case, it follows that the opening isprovided in the circuit board 70. However, since the cap portion 20 iscontained in the opening, the circuit board 70 is kept from contact withthe cap portion 20, in the same manner as described above.

Thus, even when the bumps 60 are lower than the cap portion 20 relativeto the sensor portion 10, the circuit board 70 can be flip-chip mountedon the sensor portion 10 by providing the depressed portion 71 or theopening in the circuit board 70.

Fourteenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to each of theembodiments. The present embodiment is characterized in that two chipshaving respective wiring pattern portions are bonded to compose asemiconductor device.

FIG. 21 is a schematic cross-sectional view of the semiconductor deviceaccording to the present embodiment. As shown in the drawing, thesemiconductor device comprises a first chip 80 and a second chip 90bonded to each other.

The first chip 80 has a plate-like shape with a surface, and has a firstIC circuit portion 81 provided in the surface layer portion of thesurface. The first chip 80 has a wiring pattern portion 82 having thesame structure as that of the wiring pattern portion shown in FIG. 2.

Specifically, a first insulating film 83 is formed on the first ICcircuit portion 81. On the first insulating film 83, a first wiringlayer 84 to be connected to the first IC portion 81 is patterned. Inaddition, a second insulating film 85 provided with opening parts 85 aexposing the first wiring layer 84 is formed on the first wiring layer84. On the first wiring layer 84 exposed from the opening parts 85 a, asecond wiring layer 86 is formed. The wiring pattern portion 82 iselectrically connected to the first IC circuit portion 81, though notshown in FIG. 21.

Likewise, the second chip 90 has a plate-like shape with a surface, andhas a second IC circuit portion 91 provided in the surface layer portionof the surface. The second chip 90 also has a wiring pattern portion 92having the same structure as that of the wiring pattern portion 82described above, which is formed on the second IC circuit portion 91.

Specifically, a first insulating film 93 is formed on the second ICcircuit portion 91. On the first insulating film 93, a first wiringlayer 94 to be connected to the second IC portion 91 is patterned. Inaddition, a second insulating film 95 provided with opening parts 95 aexposing the first wiring layer 94 is formed on the first wiring layer94. On the first wiring layer 94 exposed from the opening parts 95 a, asecond wiring layer 96 is formed. It will easily be appreciated that thewiring pattern portion 92 is electrically connected to the second ICcircuit portion 91.

The surface of the first chip 80 and the surface of the second chip 90are oriented to face each other, and the second wiring layer 86 of thewiring pattern portion 82 of the first chip 80 and the second wiringlayer 96 of the wiring pattern portion 92 of the second chip 90 arebonded to each other.

The size of the first chip 80 is smaller than the size of the secondchip 90 so that the second wiring layer 96 of the second chip 90 isexposed from the first chip 80. To the exposed second wiring layer 96,the bonding wires 31 are connected to electrically connect thesemiconductor device and the outside.

The semiconductor device having such a structure is manufactured asfollows. As shown in FIG. 22, the first chip 80 formed with the first ICcircuit portion 81 and with the wiring pattern portion 82, and thesecond chip 90 formed with the second IC circuit portion 91 and with thewiring pattern portion 92 are prepared.

In the first chip 80, the height of the second wiring layer 86 is thesame relative to the surface of the first chip 80 at any place.Likewise, in the second chip 90, the height of the second wiring layer96 is also the same relative to the surface of the second chip 90 at anyplace.

The chips 80 and 90 shown in FIG. 22 are each formed in a wafer state.In a wafer formed with a large number of the first chips 80, throughholes are formed in respective portions where the bonding wires aredisposed.

Then, the individual wafers are bonded at a room temperature. At thistime, the second wiring layer 86 of the wiring pattern portion 82 of thefirst chip 80 and the second wiring layer 96 of the wiring patternportion 92 of the second chip 90 are bonded to each other. Thereafter,each of the wafers is cut and divided by dicing, whereby thesemiconductor devices each shown in FIG. 21 are completed.

By thus providing the individual chips 80 and 90 with the respectivewiring pattern portions 82 and 92, and bonding the individual wiringpattern portions 82 and 92 to each other, each of the semiconductordevices can be formed. In this case, because it is unnecessary toprovide a complicated wiring pattern in each of the circuit portions 81and 91, the area occupied by the circuit portions 81 and 91 can beprevented from increasing, and consequently, the size of each of thechips 80 and 90 can be prevented from increasing. In addition, since thewiring pattern portions 82 and 92 of the individual chips 80 and 90 aremerely bonded, the process of manufacturing the semiconductor device canbe simplified.

Fifteenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the fourteenthembodiment. The present embodiment is characterized in that the wiringpattern portions 82 and 92 are provided with respective hermeticallysealing parts.

FIG. 23 is a schematic cross-sectional view of the semiconductor deviceaccording to the present embodiment. As shown in the drawing, in thefirst chip 80, a hermetically sealing part 86 a is formed on the secondinsulating film 85 of the wiring pattern portion 82. As shown in FIG.3B, the hermetically sealing part 86 a is in an annular shape having oneend connected to the other end thereof. The hermetically sealing part 86a is formed on the second insulating film 85 to be electricallyinsulated from the first wiring layer 84 and have the same height asthat of the second wiring layer 86.

Likewise, in the second chip 90, a hermetically sealing part 96 a, whichis the same as the hermetically sealing part 86 a described above, isalso formed on the second insulating film 95.

The individual second wiring layers 86 and 96 are bonded, and theindividual hermetically sealing parts 86 a and 96 a are bonded tohermetically seal the space defined by the hermetically sealing parts 86a and 96 a, the first insulating film 83 and 93, and the secondinsulating films 85 and 95.

By thus providing the individual wiring pattern portions 82 and 92 withthe annular hermetically sealing parts 86 a and 96 a having the sameheights as those of the second wiring layers 86 and 96, the entrance ofwater vapor, moisture, ions, and the like from the outside can beprevented, and the hermetically sealed space can be protected fromcontamination from the outside.

Because the hermetically sealed space is immune to influence from theoutside, e.g., the influence of a temperature or the like, it ispossible to prevent variations in the characteristics of the individualcircuit portions 81 and 91.

Sixteenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to each of theembodiments. In each of the embodiments described above, thesemiconductor dynamic quantity sensor or semiconductor device whichdetects an acceleration in a direction parallel with the surface of thesensor portion 10 is shown by way of example. In the present embodiment,by contrast, a description will be given of a semiconductor dynamicquantity sensor which detects an acceleration in a directionperpendicular to the surface of the sensor portion 10.

FIG. 24 is a plan view of the semiconductor dynamic quantity sensoraccording to the present embodiment. FIG. 25 is a cross-sectional viewalong the line XXV-XXV of FIG. 24. Although the sensor portion 10 isprimarily shown in the plan view of FIG. 24, a part of the first wiringlayer 23 of the cap portion 20 is also shown therein.

As shown in FIG. 24, beam portions 100 and a movable electrode 110 areprovided in the region of the sensor portion 10 encircled by theperipheral portion 19. As shown in FIG. 25, each of the beam portions100 is formed on the insulating layer 13 made of SiO₂ or the like. Themovable portion 110 is formed by etching a part of the first siliconlayer 11 into the plate-like shape shown in FIG. 24. The movableelectrode 110 has a side surface thereof connected to the beam portions100. The movable electrode 110 is provided with a large number ofthrough holes 111. On the movable electrode 110, the wiring layer 14 isleft.

The insulating layer 13 between the movable electrode 110 and the secondsilicon layer 12 is removed so that the movable electrode 110 is in astate floating over the second silicon layer 12. That is, a lower gap ofa height corresponding to the thickness of the insulating layer 13between the movable electrode 110 and the second silicon layer 12 isformed under the movable electrode 110. On the other hand, an upper gapof a height corresponding to the thickness of the second wiring layer 25is formed between the wiring layer 14 on the movable electrode 110 andthe second insulating film 24 of the cap portion 24. As a result, themovable electrode 110 serves as a spindle which can move in thedirection indicated by the arrow shown in FIG. 25, i.e., in thedirection perpendicular to the surface of the sensor portion 10. Thedirection perpendicular to the surface of the sensor portion 10 will behereinafter referred to as a Z-axis.

The beam portions 100 and the movable electrode 110 are encircled by thehermetically sealing part 25 b bonded to the peripheral portion 19, anddisposed in the sealed space.

In addition, the cap portion 20 has the first wiring layer 23 formed ata position which opposes the movable electrode 110 when the cap portion20 and the sensor portion 10 are bonded to each other. The first wiringlayer 23 is sandwiched between the first insulating film 22 and thesecond insulating film 24. A capacitor is formed using the first wiringlayer 23 as an upper electrode (fixed electrode) and using the movableelectrode 110 as a lower electrode.

In such a semiconductor device, when the movable electrode 110 vibratesin the Z-axis direction, a change in the distance between the firstwiring layer 23 and the movable electrode 110 is detected. Morespecifically, a change in the distance between the wiring layer 14 onthe movable electrode 110 and the first wiring layer 23 is detected.That is, an acceleration in the Z-axis direction is obtained bydetecting the capacitance of the capacitor which varies with the changein the distance.

The movable electrode 110 can be formed by, e.g., the same manufacturingmethod as that for the movable electrode portion 16 shown in FIG. 1. Thepresent embodiment shows the beam portions 100 each formed to have thesame thickness as that of the first silicon layer 11 of the SOIsubstrate. However, it is also possible to reduce the thickness of eachof the beam portions 100 as necessary. In that case, it is important toaccurately form the gap for the detection of the capacitance in theZ-axis direction between the movable electrode 110 and the first wiringlayer 23 with no fluctuation. The present embodiment uses a CVDmultilayer deposition method, a sputtering method, or the like whichallows the formation of the beam portions 100 each having an accuratethickness.

As described above, a part of the first wiring layer 23 of the capportion 20 can be used as the fixed electrode of a sensor for detectingan acceleration, and the acceleration in the Z-axis direction can bedetected. In addition, the beam portions 100 and the movable electrode110 can be hermetically sealed by the hermetically sealing part 25 b.This can prevent the movable electrode 110 from receiving influence fromthe outside and improve the accuracy of acceleration detection.

Seventeenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the sixteenthembodiment. FIG. 26 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. As shown in the drawing, the wiring layer 14 is removed fromabove the movable electrode 110 in the present embodiment. As a result,the upper gap of a height corresponding to the combined thickness of thesecond wiring layer 25 and the wiring layer 14 removed from above themovable electrode 110 is formed. Accordingly, the gap between the secondinsulating film 24 and the movable electrode 110 is vertically widerthan in the case where the wiring layer 14 is formed on the movableelectrode 110. As a result, it is possible to prevent the movableelectrode 110 moving in the Z-axis direction from contacting the secondinsulating film 24.

In addition, the wiring layer 14 is also removed from above theperipheral portion 19. Thus, the portion of the wiring layer 14 which isnot bonded to the cap portion 20 is removed from the first silicon layer11. In other words, only the portion of the wiring layer 14 which isbonded to the wiring part 25 a and the hermetically sealing part 25 b ofthe second wiring layer 25 of the cap portion 20 is provided on thefirst silicon layer 11.

By thus forming the wiring layer 14 only in the area of the firstsilicon layer 11 needed for the bonding of the sensor portion 10 and thecap portion 20, the influence of the difference in thermal expansioncoefficient between silicon and metal can be reduced.

Eighteenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the seventeenthembodiment. FIG. 27 is a schematic cross-sectional view of thesemiconductor dynamic quantity sensor according to the presentembodiment. As shown in the drawing, in the present embodiment, acounter electrode 25 c is formed in the area of the second insulatingfilm 24 opposing the movable electrode 110. The counter electrode 25 cis formed as the second wiring layer 25 on the second insulating film24, simultaneously with the wiring part 25 a. The counter electrode 25 cis electrically connected to the first wiring layer 23 via the openingparts 24 a provided in the second insulating film 24.

The counter electrode 25 c is formed of, e.g., Al or polysilicon. Thewiring layer 14 is also formed of Al or polysilicon.

In the present embodiment, the wiring layer 14 is removed from themovable electrode 100 so that the upper gap of a height corresponding tothe thickness of the wiring layer 14 removed from the movable electrode110 is formed. The acceleration in the Z-axis direction is detected bydetecting a change in the distance between the movable electrode 110 andthe counter electrode 25 c.

Thus, by providing the counter electrode 25 c on the second insulatingfilm 24, the distance between the movable electrode 110 and the counterelectrode 25 c can be reduced to a value smaller than in the case wherethe first wiring layer 23 is used as the fixed electrode. Accordingly,the output range of a detected value can be widened.

Nineteenth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the eighteenthembodiment. FIG. 28A is a schematic plan view of the semiconductordynamic quantity sensor according to the present embodiment. FIG. 28B isa cross-sectional view along the line C-C of FIG. 28A. In FIGS. 28A and28B, only the peripheral portion 19 and the movable electrode 110 areshown, and the other members are omitted.

As shown in FIG. 28A, in the present embodiment, the beam portions 100are provided at two places which are a side surface 112 of the movableelectrode 110 and a side surface 113 thereof opposite to the sidesurface 112. The individual beam portions 100 connect the peripheralportion 19 and the movable electrode 110 to be located on mutuallyopposite sides. As a result, as shown in FIG. 28B, the side surface 114of the movable electrode 110, which is among the two side surfaces 114and 115 each perpendicular to the side surfaces 112 and 113 of themovable electrode 110, and more distant from the beam portions 100 thanthe side surface 115, greatly moves, while the side surface 115 closerto the beam portions 110 moves less greatly than the side surface 114.In this case, the beam portions are twisted in the direction of themovement.

As shown in FIG. 28B, the cap portion 20 has the first wiring layer 23as the fixed electrode, which is divided and provided in the respectiveareas of the movable electrode 110 opposing the side surface 114 and theside surface 115.

As a result, when the movable electrode 110 moves in the Z-axisdirection, the side thereof adjacent the side surface 114 moves closerto the first wiring layer 23, while the side of the movable electrode110 adjacent the side surface 115 moves away from the first wiring layer23. Conversely, when the side of the movable electrode 110 adjacent theside surface 114 moves away from the first wiring layer 23, the side ofthe movable electrode 110 adjacent the side surface 115 moves closer tothe first wiring layer 23. By detecting a change in the capacitancebetween the movable electrode 110 which moves and the first wiring layer23, the acceleration in the Z-axis direction can be detected.

In the case shown in FIG. 28, the wiring layer 14 is not provided in themovable electrode 110. However, it will easily be appreciated that thewiring layer 14 may also be provided therein. As shown in FIG. 27, thecounter electrode 25 c may also be divided and provided on therespective sides of the movable electrode 110 adjacent the side surface114 and the side surface 115 in the cap portion 20.

As described above, it is also possible to detect the acceleration inthe Z-axis direction by providing the two side surfaces 112 and 113 ofthe movable electrode 110 with the beam portions 100 connected to themovable electrode 110.

Twentieth Embodiment

In the present embodiment, a description will be given only of a portiondifferent from the semiconductor device according to the eighteenthembodiment. FIG. 29A is a schematic plan view of the semiconductordynamic quantity sensor according to the present embodiment. FIG. 29B isa cross-sectional view along the line D-D of FIG. 29A. In FIGS. 29A and29B, only the peripheral portion 19 and the movable electrode 110 areshown, and the other members are omitted.

As shown in FIG. 29A, two through holes 116 are provided on the side ofthe movable electrode 110 adjacent the side surface 115 to be arrangedin the direction perpendicular to the side surface 115. The portioninterposed between the through holes 116 serves as the beam portion 110.The beam portion 110 is a part of the first silicon layer 11, and fixedto the second silicon layer 12 via the insulating layer 13. Accordingly,by the twisting of the beam portion 100, the respective sides of themovable electrode 110 adjacent the side surfaces 114 and 115 are allowedto move in the Z-axis direction.

Therefore, in the same manner as in the nineteenth embodiment, theacceleration in the Z-axis direction is detected by detecting a changein the distance between the first wiring layer 23 and the side of themovable electrode 110 adjacent the side surface 114 as well as a changein the distance between the first wiring layer 23 and the side thereofadjacent the side surface 115.

As shown in FIG. 24, it is also possible to provide a large number ofthe through holes 111 in the movable electrode 110. It is also possibleto detect a change in the distance between the counter electrode 25 cshown in FIG. 27 and each of the sides adjacent the side surfaces 114and 115, not between the first wiring layer 23 and each of the sidesadjacent the side surfaces 114 and 115.

Thus, by providing the structure in which the beam portion 110 isdisposed within the range of the movable electrode 110 and twisted, theacceleration in the Z-axis direction can be detected.

Other Embodiments

In each of the embodiments described above, the semiconductor deviceprovided with the hermetically sealing part 25 b is shown. However, thehermetically sealing part 25 b functions to hermetically seal the sensorstructures 15 to 17, and need not necessarily be provided in thesemiconductor device. In other words, the semiconductor device may alsohave a structure which is not provided with the hermetically sealingpart 25 b.

In each of the embodiments described above, N-type monocrystallinesilicon is used for each of the silicon layers 11 and 12 of the sensorportion 10. However, it is also possible to use, e.g., an N⁺-typemonocrystalline silicon. Although the silicon substrate 21 and thesilicon layers 11 and 12 that have been used heretofore are each at ahigh concentration, it is also possible to use a substrate and layersobtained by implanting impurity ions into a low-concentration substrateand low-concentration layers, or a substrate and layers each obtained byincreasing the concentration of the entire part or only a surfacethereof by a vapor-phase impurity diffusion method or the like.

In each of the embodiments described above, the silicon substrate 21 isused for the cap portion 20. However, it is also possible to use aninsulating material such as, e.g., glass. This obviates the necessityfor the first insulating film 22, and allows the first wiring layer 23to be formed directly on the insulating material.

The first wiring layer 23 can also be formed of doped polysilicon.Further, it is also possible to use doped polysilicon for the secondwiring layer 25. In the case of using polysilicon, a silicon-siliconjunction is formed by room-temperature bonding so that the mechanicalstrength and stability are improved. In this case, Al layers may beformed only on the bonding pad portions for wire bonding. For moresimplification, it is possible to form an Al, Au, or Cu printed layer onthe bonding pad portions by an ink jet method, a screen printing method,or the like, and perform a thermal process as necessary to increaseadhesion, and perform wire bonding with respect to the regions.

In the twelfth embodiment, the bumps 60 are provided in the sensorportion 10. However, it is also possible to perform flip-chip mounting(ball bonding) with respect to the cap portion 20. In this case, astress placed on the sensor portion 10 from the outside can further bereduced.

In the twelfth and thirteenth embodiments, the IC circuit portion 50 isprovided on the side of the cap portion 20 facing the sensor portion 10.However, it is also possible to provide the IC circuit portion 50 on theside opposite to the side of the cap portion 20 to be bonded to thesensor portion 10, i.e., on the side with the circuit board 70.

In the fourteenth and fifteenth embodiments, the chips 80 and 90 areshown which have the respective circuit portions 81 and 91 formed onlyin the surface layer portions of the surfaces thereof. However, they areonly illustrative, and the circuit portions may also be provided in thesurface layer portions of the surfaces opposite to the foregoingsurfaces. In this case, the respective circuit portions provided on theboth surfaces may be connected appropriately by through electrodesextending through the chips 80 and 90.

The movable electrode 110 which moves in the Z-axis direction shown ineach of the sixteenth to twentieth embodiments can be used not only inthe acceleration sensor, but also as the drive electrode of a Gyrosensor (in this case, the detection electrode serves as an electrodemovable in parallel with a substrate in a comb-teeth shape), or as thedetection electrode of the Gyro sensor (in this case, the movableelectrode 110 serves as the electrode movable in parallel with thesubstrate in a comb-teeth shape).

In the embodiments described above, the individual acceleration sensorseach for detecting the acceleration in the Z-axis direction or in thedirection perpendicular to the Z-axis direction have been described.However, it is also possible to produce a biaxial acceleration sensor inwhich an acceleration sensor for detecting the acceleration in theZ-axis direction and an acceleration sensor for detecting theacceleration in the direction perpendicular to the Z-axis direction areintegrated on a single chip. Likewise, it is also possible to integratesensors capable of respectively detecting accelerations along theZ-axis, along the X-axis, and along a Y-axis perpendicular to the X-axisand the Z-axis on a single chip. In this case, each of the accelerationsensors for detecting the accelerations in the individual axisdirections can be individually encircled by the hermetically sealingpart 25 b, or all the acceleration sensors can also be encircled by asingle hermetically sealing part 25 b.

While the invention has been described with reference to preferredembodiments thereof, it is to be understood that the invention is notlimited to the preferred embodiments and constructions. The invention isintended to cover various modification and equivalent arrangements. Inaddition, while the various combinations and configurations, which arepreferred, other combinations and configurations, including more, lessor only a single element, are also within the spirit and scope of theinvention.

1. A semiconductor device comprising: a sensor element having a plateshape with a surface and including a sensor structure disposed in asurface portion of the sensor element; and a plate-shaped cap elementbonded to the surface of the sensor element, wherein: the cap elementhas a wiring pattern portion facing the sensor element; the wiringpattern portion connects an outer periphery, including a peripheralportion surrounding the sensor structure, of the surface of the sensorelement and the sensor structure so that the sensor structure iselectrically coupled with an external element via the outer periphery;the wiring pattern portion includes: a first wiring layer for connectingthe outer periphery of the surface of the sensor element and the sensorstructure, a first insulation film disposed on the first wiring layer,and having a first opening, which faces the sensor structure and theouter periphery of the surface of the sensor element so that the firstwiring layer is exposed from the first insulation film in the firstopening, and a second wiring layer including a wiring part, which isdisposed on the first wiring layer exposed from the first insulationfilm in the first opening, and further including a hermetically sealingpart, which has a ring shape and faces the peripheral portion of theouter periphery, wherein the wiring part is coupled with the sensorstructure, and is further coupled with the outer periphery of thesurface of the sensor element; the hermetically sealing part is disposedon the first insulation film so that the hermetically sealing part iselectrically insulated from the first wiring layer; the hermeticallysealing part is bonded to the peripheral portion so that the sensorstructure is sealed and accommodated in a space defined by the capelement and the sensor element; the cap element has a silicon substrate,a second insulation film on the silicon substrate and a first conductioncontact portion; the second insulation film has a second opening forexposing the silicon substrate via the second opening; the firstconduction contact portion is disposed in the second opening, andelectrically connects the silicon substrate and the first wiring layer;the wiring pattern portion further includes a second conduction contactportion, which is disposed in the first opening; the second conductioncontact portion electrically connects the first wiring layer and thehermetically sealing part; and the silicon substrate electricallyconnects the peripheral portion of the sensor element via the firstconduction contact portion, the first wiring layer, the secondconduction contact portion and the hermetically sealing part.
 2. Thesemiconductor device of claim 1, wherein: the outer periphery of thesensor element further includes a connection portion for connecting awire to the external element; the connection portion is disposed on anoutside of the peripheral portion; and the wiring part is bonded to theconnection portion so that the sensor structure is coupled with theexternal element via the connection portion and the wire.
 3. Thesemiconductor device of claim 1, wherein: the sensor element has an SOIsubstrate comprising a first silicon layer, a second silicon layer andan insulation layer; the sensor structure is disposed in the firstsilicon layer; the insulation layer is sandwiched between the firstsilicon layer and the second silicon layer; the peripheral portion isdisposed in the first silicon layer; the insulation layer has a thirdopening, in which a substrate contact part is disposed; and thesubstrate contact part is disposed between the peripheral portion andthe second silicon layer to electrically connect the peripheral portionand the second silicon layer.
 4. The semiconductor device of claim 3,wherein: the sensor element has a third wiring layer on the firstsilicon layer; and the cap element is bonded to the third wiring layer.5. A semiconductor device comprising: a first chip having a plate shapewith a first surface and including a first IC circuit portion, which isdisposed in a first surface portion of the first chip; and a second chiphaving a plate shape with a second surface and including a second ICcircuit portion, which is disposed in a second surface portion of thesecond chip, wherein: the first chip further includes a first wiringpattern portion comprising a first insulating film, a first wiringlayer, a second insulating film and a second wiring layer; the firstinsulating film is disposed on the first IC circuit portion; the firstwiring layer is patterned on the first insulating film and coupled withthe first IC circuit portion; the second insulating film is disposed onthe first wiring layer; the second insulating film has a first openingso that the first wiring layer is exposed from the second insulatingfilm via the first opening; the second wiring layer is disposed on thefirst wiring layer exposed in the first opening; the second chipincludes a second wiring pattern portion comprising a third insulatingfilm, a third wiring layer, a fourth insulating film and a fourth wiringlayer; the third insulating film is disposed on the second IC circuitportion; the third wiring layer is patterned on the third insulatingfilm and coupled with the second IC circuit portion; the fourthinsulating film is disposed on the third wiring layer; the fourthinsulating film has a second opening so that the third wiring layer isexposed from the fourth insulating film via the second opening; thefourth wiring layer is disposed on the third wiring layer exposed fromthe second opening; the surface of the first chip faces the surface ofthe second chip; the second wiring layer of the first wiring patternportion of the first chip and the fourth wiring layer of the secondwiring pattern portion of the second chip are bonded to each other; thefirst wiring pattern portion further includes a first hermeticallysealing part on the second insulating film, and the second wiringpattern portion further includes a second hermetically sealing part onthe fourth insulating film; each of the first and second hermeticallysealing parts has an annular shape; the first hermetically sealing partis electrically insulated from the first wiring layer, and has a heightequal to the second wiring layer; the second hermetically sealing partis electrically insulated from the third wiring layer, and has a heightequal to the fourth wiring layer; and the first hermetically sealingpart of the first chip and the second hermetically sealing part of thesecond chip are bonded to each other for sealing a space defined by thefirst and second hermetically sealing parts, the first and secondinsulating films, and the third and fourth insulating films.
 6. Asemiconductor device comprising: a sensor element having a plate shapewith a surface and including a sensor structure disposed in a surfaceportion of the sensor element, and a peripheral portion, which surroundsthe sensor structure; and a plate-shaped cap element bonded to thesurface of the sensor element, wherein: the cap element has a wiringpattern portion facing the sensor element; the wiring pattern portionincludes: a first wiring layer formed on a surface of the cap elementopposing the sensor portion; a first insulation film disposed on thefirst wiring layer; and a second wiring layer including a wiring part,which is disposed on the first wiring layer exposed from the firstinsulation film, and a hermetically sealing part, which has a ring shapeand faces the peripheral portion; the hermetically sealing part isdisposed on the first insulation film so that the hermetically sealingpart is electrically insulated from the first wiring layer; thehermetically sealing part is bonded to the peripheral portion so thatthe sensor structure is sealed and accommodated in a space defined bythe cap element and the sensor element; the wiring part is coupled withthe sensor structure; the wiring part is further exposed from the spaceso that the sensor structure is coupled with an external element; andthe wiring part contacts a wire for connecting the external element sothat the sensor structure is coupled with the external element via thewiring part and the wire.
 7. The semiconductor device of claim 6,wherein: the first insulation film has a first opening, which faces thesensor structure so that the first wiring layer is exposed from thefirst insulation film in the first opening.
 8. The semiconductor deviceof claim 6, wherein: the cap element further includes an IC circuitportion, which is disposed in a surface portion of the cap element andopposite to the sensor element.
 9. The semiconductor device of claim 6,wherein: the cap element further includes an IC circuit portion, whichis disposed in a surface portion of the cap element and faces the sensorelement.
 10. The semiconductor device of claim 6, wherein: the capelement further includes a recessed part, which faces at least thesensor structure, and is not disposed on the wiring part.
 11. Thesemiconductor device of claim 6, wherein: the cap element has a siliconsubstrate, a second insulation film on the silicon substrate and a firstconduction contact portion; the second insulation film has a secondopening for exposing the silicon substrate via the second opening; thefirst conduction contact portion is disposed in the second opening, andelectrically connects the silicon substrate and the first wiring layer;the wiring pattern portion further includes a second conduction contactportion, which is disposed in the first opening; the second conductioncontact portion electrically connects the first wiring layer and thehermetically sealing part; and the silicon substrate electricallyconnects the peripheral portion of the sensor element via the firstconduction contact portion, the first wiring layer, the secondconduction contact portion and the hermetically sealing part.
 12. Thesemiconductor device of claim 11 wherein: the sensor element has an SOIsubstrate comprising a first silicon layer, a second silicon layer andan insulation layer; the sensor structure is disposed in the firstsilicon layer; the insulation layer is sandwiched between the firstsilicon layer and the second silicon layer; the peripheral portion isdisposed in the first silicon layer; the insulation layer has a thirdopening, in which a substrate contact part is disposed; and thesubstrate contact part is disposed between the peripheral portion andthe second silicon layer to electrically connect the peripheral portionand the second silicon layer.
 13. The semiconductor device of claim 12,wherein: the sensor element has a third wiring layer on the firstsilicon layer; and the cap element is bonded to the third wiring layer.14. The semiconductor device of claim 6, wherein: the sensor structureincludes a movable electrode movable within the sensor element; thefirst wiring layer faces the movable electrode; and the sensor elementdetects distance change between the first wiring layer and the movableelectrode so that the sensor element detects acceleration in a directionperpendicular to the surface of the sensor element.
 15. Thesemiconductor device of claim 14, wherein: the wiring pattern portionfurther includes a counter electrode; the counter electrode is disposedon the first insulation film, and faces the movable electrode; and thesensor element detects distance change between the movable electrode andthe counter electrode, which corresponds to the distance change betweenthe first wiring layer and the movable electrode.